The present invention relates to a motor comprising an armature, a rotor and a motor casing for holding them and a method for producing the motor.
Generally, a DC motor or a DC brushless motor is used as a motor engine for vehicles such as electric vehicles and electric scooters. Such a type of motor includes an armature, a rotor and a motor casing for holding the armature and bearings for the rotor, and the armature and the rotor are disposed on the motor casing.
With recent progress of the control technology and enhancement of the performance of permanent magnets, the achievement of high rotations and high torque has become possible for the aforesaid motor. As a result, problems of connection accuracy between an output shaft of a rotor and a reduction gearing, coaxiality between an armature and a rotor, and heat radiation of a coil wound around the armature have become significant issues in satisfactorily securing the performance of the motor.
Under the circumstances described above, it is an object of the present invention to provide a motor which can provide output more efficiently and a method for producing the motor.
As the motor for the aforesaid running motor engine, there is proposed, for example, Japanese Patent Application Laid-Open Publication No. Hei 10-234158 which describes an electric motor including an armature, a rotor, a control section for controlling the armature and a motor casing for holding them.
Thus, the motor casing is configured to hold the control section together. Therefore, it is easy to secure an installing space and to mount the motor as compared with a design that the control section is separately provided.
The motor used for the aforesaid running motor engine or the like needs the motor casing to have airtightness in order to prevent water and dust from entering from outside.
But, because the motor casing which holds the armature, the rotor and the control section is generally configured by assembling a plurality of members respectively covering the armature, the rotor and the control section, it has many joints which are in contact with outside and, therefore, a disadvantage in securing airtightness.
In view of the aforesaid problems, it is an object of the present invention to provide a motor having the airtightness of the motor casing improved further more.
The invention described in claim 1 is a motor comprising an armature, a rotor and a motor casing for holding the armature and a bearing for the rotor, characterized by a reduction gearing consisting of a train of gears connected to an output shaft of the rotor and a reduction gearing casing for holding the reduction gearing, the motor casing being integrally provided with the reduction gearing casing, a hole, through which the output shaft is extended from the motor casing side to the reduction gearing casing side, being formed on a portion shared by these casings, and a lubrication oil filling the reduction gearing casing.
Thus, the motor of claim 1 has the reduction gearing consisting of the train of gears connected to the output shaft of the rotor and the reduction gearing casing for holding the reduction gearing, the motor casing is integrally provided with the reduction gearing casing, the hole, through which the output shaft being extended from the motor casing side to the reduction gearing casing side, formed on the portion shared by these casings, and the lubrication oil filling the reduction gearing casing. Therefore, the armature, the rotor, the bearing and the reduction gearing are accurately arranged, smoothness of the reduction gearing is secured by the lubrication oil, and power of the motor is obtained more efficiently.
If the motor casing and the reduction gearing casing have different bodies, the number of components increases, and the manufacturing cost rises. In addition, when the output shaft and the reduction gearing are mutually connected, their fitting positions and angles tend to have a subtle deviation, resulting in possible lowering of the power. But, the present invention avoids such problems without fail.
The invention described in claim 2 is the motor according to claim 1, wherein the bearing for the rotor and an oil seal for sealing the lubrication oil are placed in the hole, and the bearing is immersed in the lubrication oil.
In the motor of claim 2, the bearing for the rotor and the oil seal for sealing the lubrication oil are placed in the hole, and the bearing is immersed in the lubrication oil. Therefore, smoothness of the bearing for the rotor can be secured by the lubrication oil filling in the reduction gearing casing.
The invention described in claim 3 is a motor comprising an armature, a rotor and a motor casing for holding the armature and a bearing for the rotor, wherein the motor casing is configured by assembling a plurality of members, and at least one of the plurality of members supports the bearing and the inner diameter section of the armature.
Thus, in the motor of claim 3, the motor casing comprises the plurality of members assembled, and at least one of the plurality of members supports the bearing and the inner diameter section of the armature. Therefore, the center axis of the armature and the center axis of the rotor can be aligned accurately, and power of the motor can be obtained more efficiently.
Specifically, when the plurality of members are assembled to form the motor casing, clearances and dimensional errors of the respective members are accumulated, possibly degrading coaxiality between the armature and the rotor and adversely effecting on the motor performance. But, such a drawback can be avoided without fail because at least one of the members of the present invention supports the bearing and the inner diameter part of the armature.
The invention described in claim 4 is a motor comprising an armature, a rotor and a motor casing for holding the armature and a bearing for the rotor, wherein a resin is charged into and cured in the motor casing to adhere to a coil of the armature and the inner surface of the motor casing.
Thus, according to the motor of claim 4, the resin is charged into and cured in the motor casing to adhere to the coil of the armature and the inner surface of the motor casing. Therefore, heat radiation of the coil of the armature can be secured sufficiently. As a result, power of the motor can be obtained more efficiently.
Especially, when the resin is provided to secure the heat radiation of the coil of the armature, a metal mold corresponding to the inner surface of the motor casing was conventionally used to form the resin around the coil of the armature, and the formed unit was fitted to the motor casing. Therefore, adhesion between the resin and the inner surface of the motor casing was poor, and its heat radiation was insufficient. Accordingly, the present invention charges the resin into the motor casing for curing it therein, so that the resin and the inner surface of the motor casing can be adhered securely, and heat radiation can be improved. And, the conventional metal mold is not needed to form the resin.
The invention described in claim 5 is a method for producing a motor comprising an armature, a rotor and a motor casing for holding the armature and a bearing for the rotor, comprises the step of: charging a resin into and curing in the motor casing to adhere the resin to a coil of the armature and the inner surface of the motor casing.
Thus, according to the method for producing the motor of claim 5, the resin is charged into and cured in the motor casing, to adhere to the coil of the armature and the inner surface of the motor casing, so that the heat radiation of the coil of the armature can be secured satisfactorily. As a result, power of the motor can be obtained more efficiently.
Especially, when the resin is disposed to secure the heat radiation of the coil of the armature, a metal mold corresponding to the inner surface of the motor casing was conventionally used to form the resin around the coil of the armature, and the formed unit was fitted to the motor casing. Therefore, adhesion between the resin and the inner surface of the motor casing was poor, and its heat radiation was insufficient. Accordingly, the present invention charges the resin into and cures it in the motor casing, so that the resin and the inner surface of the motor casing can be adhered more securely, and heat radiation can be improved. And, the conventional metal mold is not needed to form the resin.
The invention described in claim 6 is the method for producing a motor according to claim 5, wherein when the resin is charged into the motor casing, a core for securing a space for placing the rotor is inserted into the motor casing.
Thus, the method for producing the motor of claim 6 charges the resin into the motor casing with the core for securing the space, in which the rotor is disposed, inserted into the motor casing, so that the rotor and the resin can be disposed efficiently.
The invention described in claim 7 is the method for producing a motor according to claim 6, wherein the motor is provided with a rotation sensor for detecting a rotation position of the rotor, and the core secures a space for placing the rotation sensor.
As described above, according to the method for producing the motor of claim 7, the motor is provided with the rotation sensor for detecting a rotation position of the rotor, and the core secures the space for disposing the rotation sensor. Thus, the rotation sensor can be disposed efficiently.
The invention described in claim 8 is a motor comprising an armature, a rotor, a control section for controlling the armature and a motor casing for holding them, wherein the motor casing includes a first casing member and a second casing member which cover the armature and the rotor and are respectively provided with bearings for the rotor and a third casing member for covering the control section, the first casing member and the third casing member are assembled to form an outer shell of the motor, the first casing member and the second casing member are assembled to divide the inside of the motor, and seating surfaces to be mutually contacted are respectively formed on ends of the first casing member and the third casing member.
According to the motor of claim 8, airtightness of the motor casing is improved further more.
Specifically, the motor casing for holding the armature, the rotor and the control section is configured by assembling a plurality of members which respectively cover the armature, the rotor and the control section, so that there are many joints which are exposed to outside, and it is disadvantageous in view of securing airtightness. In the present invention, however, the joint between the first casing member and the second casing member is located inside the joint between the first casing member and the third casing member, so that airtightness can be secured relatively easily.
And, the first casing member and the third casing member can be assembled accurately by virtue of the seating surfaces respectively formed thereon, and a gap in the joint can be eliminated without fail.
The invention described in claim 9 is the motor according to claim 8, wherein a through section is disposed on the second casing member through which to pass the wiring for connecting the armature with the control section.
According to the motor of claim 9, the wiring for connecting the armature and the control section within the motor casing can be arranged efficiently.
The invention described in claim 10 is the motor according to claim 8 or 9, wherein a substrate of the control section is supported by the second casing member.
According to the motor of claim 10, the control section can be arranged efficiently in the motor casing.
The invention described in claim 11 is the motor according to any of claims 8 to 10, wherein a sensor for detecting a position of the rotor is supported by the second casing member.
According to the motor of claim 11, the sensor for detecting a position of the rotor can be disposed efficiently in the motor casing.